Whatever you use you are best of using it in a fluidised media reactor (aka phosphate reactor/media reactor) to get the best performance out of it. This can be made from a coke bottle, pump, some pipe and a sponge or bought from around ?20 on ebay.

Normally I use rowaphos (freshwater tank). Great product. When the LFS ran out one time I bought phosban as no other choice. On contact with the water though it created quite a dusty affect but only temporarily but for a day or two. The worst thing though was the filter on cleaning, lots of bright orange muck despite sandwiching it between 2 layers of filter wool in a pop sock. It did work, but I switched back to rowaphos once I'd used it all up. Far cleaner in the tank. Think that may be 3:0

i use rowaphos and i have only just installed a reactor for it and i must say i can see a huge improvement in my tank.i did use it in the fiter in a bag in my other tank but wasnt as good as using the reactor,i recomend a phosphate reactor.....